The functionalist theory of crime is used by sociologists. The  functionalist theory is a reaction on the psychoanalytical theory of delinquency. The main functionalist representative was Robert Merton. The part of functionalist theory, which explains criminality starts with an idea that all people are born benign (benevolent), while deviant impulsive behavior is induced socially. The theory is sometimes called "consensus theory," because it doesn't look on the society from a conflict perspective, but from a perspective of social harmony. Functionalists have described American society as the society, which has its cultural goals and institutionalized ways for achievements of those goals. Understandably, the main goal is the money (cash, bucks, fed notes, greens). Financial success is the major goal, and the ways to achieve it are the education and employment. Education and employment are the guarantee for achievement of financial success. Functionalist used Durkheim's strain theory to explain certain periods of societal dysfunctionality. During the period of social anomie, new inventions are made and deviants are focused on the achievement of goals and don't care much about potential consequences of theirs actions. Members of lower and middle socio-economic status wish to financially succeed, but don't have the access to legitimate and institutionalized means or resources. Because the goals are not achievable, some of them turn to illegal ways to reach a prosperity. Functionalist concluded that American society doesn't emphasize the importance to respect social norms.

Different reactions are possible on social anomie such as:

1. innovation

2. social conformism

3. ritualism

4. retraction and

5. rebellion .

 Functionalist theory critics state that functionalist offer the incomplete explanation on how the distribution of goals and resources is made. They also think that functionalist hadn't fully explained the connection between social anomie and delinquent behavior. Critics state that it isn't clear which of the social reactions includes delinquency.

Conflict theories are opposite to functionalist theories. Most common views of academics are that supporters of conflict theories are extreme leftist and communists. The both theories are a form of idealism.

Situational crime prevention focuses on the measures how to reduce the circumstances and conditions for criminals to commit a crime. The theory takes different theoretical approach than most criminological theories which dealt with etiological problems “post delictum”. Situational crime prevention theory is mostly preoccupied with models, which have a purpose to reduce criminal opportunities. Instead of dealing with a past, the theory uses empirical knowledge and is focused on a future.

Situational crime prevention theory has a practical application in designing urban residences, which use security alarms systems, detectors, security doors and other security devices and technologies. The goal of improving home security is to make imagined target of crime less reachable to criminals. Tight home security will eventually require a better planning of burglary, larger efforts to get insight of home security and motivation for achievement of criminal goals. If home security surveillance and monitoring system has the latest available technology, the criminals will probably give up making a burglary.

Rational choice theory can be implemented in this case, because the crime is a choice, which includes economic dimension. If the cost of preparing burglary is too high i.e. it doesn’t pay off, the criminal will make a calculation and conclude that a target is not worth of his efforts. The doors alone will not prevent someone from entering, but the risk of being caught “in flagranti” certainly does prevent  burglaries from happening.

Two major research fields in criminology theory: etiology and phenomenology.  In situational crime prevention theory, phenomenology is more expressed than etiology. Etiology looks at causes, while phenomenology looks at types and developments of crime. Phenomenology reviews criminal statistics, changes in crime rate of violent, sexual, property, white collar and other types of crime. It also draws conclusions about crime trends and effectiveness of police, using statistical values. There are various sources of crime statistics, but the main are: the police statistics,  the Court statistics and State attorney's statistics ( public prosecutor). For example, the police makes monthly, quarterly, half yearly or yearly reports on the number presumptive criminals and reported probable crimes. The police statistics is often used to make certain changes in the police organization like: to advertise need for new employees, to change its organizational structure into higher or lower category of police station, to estimate or make security analysis of certain geographical area or city, to make changes of police management or other.

Theories which existed before positivist theory of crime were phrenology and physiognomy theories. Johann Lavater, the physiognomist, thought that the shape of the skull and some facial features had an impact on a human behavior and actions. Later,  positivist theorist of crime Cesare Lombroso took Lavater’s ideas and began exploring other physical traits of a body. Lombroso, the criminal anthropologist, not only researched the facial features and the shape of the skull, but social conditions of individual like unemployment and medical history of illnesses. He compared a large number of criminals and non-criminals using human physical traits like: ear size, hair length and other. Goring, the main criticist of Lombroso, conducted the research on crime heredity, but didn’t find any differences in facial features or other human physical traits between prison inmates, asylum inhabitants and non-criminals. The only physical difference Goring found between an experimental and control group was the significant dissimilarity in body weight and stature. The criminals in Goring’s research tends to have the lower weight and small stature. Positivist's theorists of crime argued that human behavior is pre-disposed and fully determined by individual differences and biological traits. In short, terms, what drives people towards crime is not a matter of free-will. The positivist crime theorist and criminal anthropologist Cesare Lombroso made attempts to scientifically prove his thesis that criminal offenders were physically different from  non-offenders. Lombroso stated that atavistic features are more akin to savages and criminal offenders. This view was held by many biological positivists. Positivist theory of crime presumed that scientific study of criminal behavior should find the"causes" of such behavior. They also believed that the causes of crime are beyond the control of the individual. Explanations of positivist theory were deterministic. Lombroso was influenced by Darwinian principles of evolution and used these ideas to support a thesis on inferiority of criminals. Positivist theory of crime implemented the idea of social Darwinism that individuals or groups develop certain physical and psychological attributes, which allow them to function more efficiently in the social and natural environment. We can object to positivist theories of crime that the theories never accepted the idea about the equality of gender roles. Lombroso thought that males were more lenient to a crime, because they were more masculine that females in general. Italian historian Renzo Villa thought that Lombroso's attempt to identify signs of criminality using biological traits are an inevitable result and part of the contextual development of nineteenth-century penal science and medicine. The positivist theory of crime understanding  was limited on the external appearance or phenotype properties as the way to identify the physical characteristics, which were present in criminal approach of phrenology.

In 1982, the broken windows theory was introduced by sociologists James Wilson and George Kelling. The broken windows theory is a subject of debate even today, and many criminology theorists have criticized this theory. Several empirical studies have confirmed the validity of broken windows theory, but it has received even larger critics. Critics of broken windows theory think that the theory is a fallacy and that it borders with causality. The theory states that if a building has few broken windows, and the windows aren’t repaired this will create a tendency for vandals to break more windows. Vandals will enter the building and they will continue destroying the building. Many theorists consider the experiment as the best confirmation of the broken windows theory. In the education system, the broken windows theory is often used to promote order in classrooms. It is also used as a motivation for criminal policy reforms. Theory takes a proactive stance towards criminality, i.e. it is best to prevent than to heal. Although, criminologists argue about causality, practical approach of theory is pointed on the reduction of crime. The broken windows theory makes two major claims, i.e. that further petty crime and low-level anti-social behavior will be deterred, and that major crime will be prevented. According to the theory, monitoring and maintaining urban environments in a well-ordered condition may prevent further vandalism as well as an escalation into more serious crime. Furthermore, broken windows theory suggests that a particular sequence of events could be expected in deteriorating neighborhoods and that an evidence of decay broken windows, accumulated trash, deteriorated building exteriors, which remains in the neighborhood for a reasonably long period of time causes people who live and work in the area to feel more vulnerable and to begin to withdraw. Theory can be applied on many areas of urban and rural development. Previous criminological studies, which  have researched "slums" came to the similar conclusion that the deterioration of necessary communal infrastructure and squalor will result with a drastic increase of insecurity and crime.

Exemplar Gratia, certain buildings will be more often subject to burglary than other buildings, especially when the building has unprotected and concealed entrances. There are various methods to protect the building from burglary, and it is commonly done by using various detectors such as dual technology, motion detectors or by using security doors and security windows with a protective layer. The causation aspect of this example is explained by a situational crime prevention theory.

Classical crime theory is represented by the theoretical study of Jeremy Bentham and Cesare Beccaria. Jeremy Bentham  was a founder of  English utilitarianism. Bentham thought that human beings are hedonistic and act only in their own self-interest. Utilitarianism also considered rational courses of action when people pursue own interests. Utilitarian teachings are an important part of  criminal-justice  ethics today. Neoclassical crime theory is a continuation of classical crime theory tradition. Development of neoclassical crime theory will continue in 1980 with a forming of new sociological theories, i.e. differential association and identification. Although sources that mention neoclassical school and crime theory of criminology are merely sparce, it main contribution to the field of criminology is reflected through the understanding of individual differences of the perpetrators. While classical school was wholly concern with an explanation of crime, neoclassical crime theory saw some flaws in Beccaria's theory of crime. Classical crime theory completely concentrated on the criminal act and positivist crime theory concentrated on the perpetrator. Positivist were obsessed with behavioral prediction and classicist with a crime explanation. Neoclassical crime theory sought to improve the stances towards perpetrators who should have an impact on the level of guilt and severity of punishment. Not all perpetrators should be treated in the same fashion, because the evident differences exist among them. Crime is a result of many conditions that have ultimately influenced on the perpetrators to commit it. Representative of neoclassical criminology theory, Gabriel Tarde published the book "Penal philosophy" in 1890. Gabriel Tarde was a French sociologist and founder of neoclassical criminology school. In his book Tarde criticizes classical and positivist criminology and takes the best from both criminology. Neoclassical criminology theory considers  age, gender and social class of the perpetrators. The perpetrators are people who think, feel, act and criminal behavior is learned within groups by imitation and identification.